/*
 * Anything: A flexible and easy to use data structure that combines the 
 * characteristics of a list and a hashmap into one data structure.
 * 
 * Based on a paper by Peter Sommerlad and Marcel Rueedi on 
 * 'Do-it-yourself reflection' entered at EuroPLOP 1998.
 * 
 * This library was written completely from scratch and is based only 
 * in spirit on the original Java Anything implementation written by 
 * Andre Weinand/Marcel Rueedi in 1997/99 and enhanced by Stefan Tramm 
 * in 2006.
 * 
 * Copyright (c) 2008 Thomas Marti and others. All rights reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package any.impl.util;

import java.util.Iterator;

/**
 * Base class for <tt>Iterable</tt> instances, which provides 
 * reasonably useful implementations of <tt>toString()</tt>, 
 * <tt>equals()</tt> and <tt>hashCode()</tt>.
 */
public abstract class BaseIterable<T> implements Iterable<T> {

	@Override
	public boolean equals(Object obj) {
		if (!(obj instanceof Iterable<?>)) {
			return false;
		}
		
		Iterator<?> otherIt = ((Iterable<?>)obj).iterator();
		for (Object t : this) {
			if (!otherIt.hasNext()) return false;
			if (!Utils.equals(t, otherIt.next())) return false;
		}

		if (otherIt.hasNext()) return false;
		
		return true;
	}
	
	@Override
	public int hashCode() {
		// Copied verbatim from java.util.AbstractList
		int hashCode = 1;
		for(Iterator<T> it = iterator(); it.hasNext();) {
			T obj = it.next();
			hashCode = 31 * hashCode + (obj == null ? 0 : obj.hashCode());
		}
		return hashCode;
	}
	
	@Override
	public String toString() {
	    StringBuilder builder = new StringBuilder("[");

	    for (Iterator<?> it = iterator(); it.hasNext();) {
	    	Object t = it.next();
	    	builder.append(t);
	    	if (it.hasNext()) {
	    		builder.append(", ");
	    	}
	    }
	    
	    return builder.append(']').toString();
	}
	
}
